<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>
        /* 属性选择器
        a[href]
        a[href="https://www.jd.com"]
        */
        a[target="_blank"] {
            color: red;
        }
        input[name="username"] {
            color: red;
        }
    </style>
</head>
<body>
    文本框：<input type="text" name="username">
    <br>
    密码框：<input type="password" name="password">
    <br>
    <a href="https://www.sina.com.cn" target="_self">新浪</a>
    <br>
    <a href="https://www.jd.com" target="_blank">京东</a>
    <br>
    <a>测试</a>
    <br>
    <a href="#" target="_blank">达内</a>
    <br>
    <a href="#" target="_self">云计算</a>
</body>
</html>